This invention relates to providing automated telephone number identification in telephone networks and, in particular, to improving the reliability of the automated identification procedure.
In a typical telephone network, an automatic intercept system is used to provide a variety of automated voice responses to callers who dial numbers that are not in service. The automatic intercept system is an independent system that processes all calls which terminate in central offices and which are directed to non-working, disconnected, invalid or changed numbers. These calls are routed from their corresponding terminating central offices over trunk lines to the intercept system. To reduce trunk costs, concentrators are often used to concentrate the trunk lines from different groups of central offices into trunk groups which then feed the intercept system.
In selecting the proper voice response, the intercept system is required to know the phone number of the unsuccessful call (the "called number"). Newer terminating central offices store the called number as it is received and, thus, are able to automatically recall the number for use by the intercept system. Calls of this type are typically referred to as automatic number identification (ANI) calls.
Older terminating central offices, however, are not capable of storing and, therefore, recalling the called number. Therefore, these older central offices require that the automatic intercept system first initiate an operator intervention to communicate with the caller to obtain the called number and forward it to the intercept system. Such calls requiring operator intervention are typically referred to as operator number identification (ONI) calls.
As can be appreciated, the need of an operator to process ONI calls represents a major expense to telephone companies. Accordingly, a number of proposals have been made for automating the ONI function. A first proposal requires that the caller respond to an automated voice prompt which instructs the caller to reenter the called number via a touch-tone phone. However, this proposal is of limited value, since not all callers have touch-tone service.
A second proposal makes use of speech or voice recognition. In this case, an automated voice prompt instructs the caller to reenter the called number by speaking the number. A standard speech recognition device then interprets the spoken number to generate the digits of the called number which are then conveyed to the intercept system.
The use of speech recognition is advantageous, since it is not limited to a particular type of telephone, as in the touch-tone case. However, for speech recognition to be successfully used in automating the ONI function, the speech recognition devices employed must be capable of reliably interpreting the spoken telephone number. Unfortunately, speech recognition devices available today are considerably less than one hundred percent accurate, particularly where such devices must interpret the spoken language of a large and diverse population. As a result, automated operator number identification systems using speech recognition may result in incorrect number identification which, in turn, can cause inappropriate responses to be supplied by the automatic intercept system.
It is, therefore, an object of the present invention to provide a method and apparatus which allows called numbers to be automatically and more reliably identified.
It is a further object of the present invention to provide a method and apparatus as stated in the previous objective for automating operator number identification in an automatic intercept system.